MemberInfo.IsDefined Method (Type, Boolean)


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When overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member.

Namespace:   System.Reflection
Assembly:  mscorlib (in mscorlib.dll)

public abstract bool IsDefined(
	Type attributeType,
	bool inherit


Type: System.Type

The type of custom attribute to search for. The search includes derived types.

Type: System.Boolean

true to search this member's inheritance chain to find the attributes; otherwise, false. This parameter is ignored for properties and events; see Remarks.

Return Value

Type: System.Boolean

true if one or more instances of attributeType or any of its derived types is applied to this member; otherwise, false.

This method ignores the inherit parameter for properties and events. To search the inheritance chain for attributes on properties and events, use the appropriate overloads of the Attribute.IsDefined method.


In the .NET Framework version 2.0, this method returns true if a type, method, or constructor has security attributes stored in the new metadata format. Assemblies compiled with version 2.0 use this format. Dynamic assemblies and assemblies compiled with earlier versions of the .NET Framework use the old XML format. See Emitting Declarative Security Attributes.

The following example determines whether the specified attribute is applied to the specified member.

using System;
using System.Reflection;

// Define a custom attribute with one named parameter.
public class MyAttribute : Attribute
    private string myName;
    public MyAttribute(string name)
        myName = name;
    public string Name
            return myName;

// Define a class that has the custom attribute associated with one of its members.
public class MyClass1
    [MyAttribute("This is an example attribute.")]
    public void MyMethod(int i)

public class MemberInfo_GetCustomAttributes_IsDefined
    public static void Main()
            // Get the type of MyClass1.
            Type myType = typeof(MyClass1);
            // Get the members associated with MyClass1.
            MemberInfo[] myMembers = myType.GetMembers();

            // Display the attributes for each of the members of MyClass1.
            for(int i = 0; i < myMembers.Length; i++)
                // Display the attribute if it is of type MyAttribute.
                if(myMembers[i].IsDefined(typeof(MyAttribute), false))
                    Object[] myAttributes = myMembers[i].GetCustomAttributes(typeof(MyAttribute), false);
                    Console.WriteLine("\nThe attributes of type MyAttribute for the member {0} are: \n",
                    for(int j = 0; j < myAttributes.Length; j++)
                        // Display the value associated with the attribute.
                        Console.WriteLine("The value of the attribute is : \"{0}\"",
        catch(Exception e)
            Console.WriteLine("An exception occurred: {0}", e.Message);

.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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